Hep C NS4 Activators

Hepatitis C virus (HCV) NS4 is a composite term referring to two distinct but related nonstructural proteins, NS4A and NS4B, produced by the HCV. These proteins play critical roles in the lifecycle of the virus and the disease process.NS4A is a small, hydrophobic protein that acts as a cofactor for the NS3 protease. It enhances the enzymatic function of NS3 by stabilizing its structure and aligning it in the proper orientation for catalytic activity. This protease activity is essential for the maturation of the virus, as it cleaves the HCV polyprotein at specific sites to produce the individual proteins required for virus replication.

NS4B, on the other hand, induces the formation of a membranous web within the host cell's cytoplasm, which serves as the platform for the viral replication complex. NS4B has been found to have RNA binding and NTPase (nucleoside triphosphatase) activities, suggesting active roles in the viral replication process. Both NS4A and NS4B are crucial for the replication of the HCV, and they have been targeted for the development of antiviral drugs. NS4A is a particularly attractive target because of its role in assisting the NS3 protease, which has been the focus of many of the directly acting antiviral (DAA) drugs for HCV. In summary, HCV NS4 comprises two proteins, NS4A and NS4B, which play essential roles in HCV replication.